Oxygen sensitive oils or oxygen sensitive oil soluble ingredients are a significant class of food ingredients. Because of their susceptibility to oxidation the ingredients need to be in a form that is protective as well as enhancing their ease of use. Oils that are of commercial significance which fall into this category are generally those containing polyunsaturated fatty acids.
These ingredients need to be prepared in a form suitable as ingredients for general foods, novel foods, functional foods and nutraceuticals and to be storage stable under the usual transport conditions. Usually the ingredients are processed into stable oil-in-water emulsions or stable powders depending on their end use.
Powdered oils are generally formed by encapsulating the oil in protein forming an emulsion and drying the emulsion to form a powdered oil. Japanese patent 5030906 discloses such a product made by mixing diacetyl ester tartrate monoglyceride and edible oil in an aqueous sodium caseinate solution, emulsifying and drying to form a powder.
Japanese patent 5098286 discloses the encapsulation of unsaturated fatty acids, such as gamma-linolenic acids, with hydrolysed proteins such as lactalbumin, lactoglobulin and casein to prevent oxidation of the acids.
Hydrolysed proteins vary in activity according to the degree of hydolysation and this may vary with different oils. Further the stability of the protein film encapsulating the oils is not always satisfactory. The protection against oxidation is primarily due to the hydrolysed protein preventing contact between oxygen and the unsaturated fatty acids rather than an antioxidant effect of the encapsulant.
U.S. Pat. No. 5,601,760 also discloses micro-encapsulation of milk fat and orange oils using whey proteins as the encapsulant. This patent also suggests that the whey proteins can be mixed with carbohydrates.
U.S. Pat. No. 5,143,737 discloses an animal feed supplement composed of an unsaturated oil encapsulated in a whey solution containing lactose which has been dried to form a powder and then browned to form a Maillard reaction product in the encapsulating matrix.
It is an object of this invention to provide an encapsulant that has good encapsulating properties and is also an antioxidant to protect oxygen sensitive oils or oil soluble products.